[mythtv] ringbuffer.cpp

Jonas Arndt jonas.arndt at thearndtfamily.com
Sun Feb 23 00:50:19 UTC 2014

On 02/22/2014 11:06 AM, Jonas Arndt wrote:
>>> Not sure it will work in your case anyway, you can see in your log
>>> that the BE didn't write anything for over 4s.
>>> There's no way you can handle live TV without freeze or abort when you
>>> starve playback from data for such long time.
>>> Recover from 1-2s sure... 4s... no way
>>> _______________________________________________
>> Thanks JY,
>> So the one difference between my friend's system and mine is that his 
>> HDHomeRun goes through a cheap Netgear Wifi AP router. It is NOT on 
>> Wifi but the router is only 100 Mbps and, looking at the IO Graph 
>> (Wireshark) it looks a bit iffy. Every 30 seconds the bandwidth goes 
>> down significantly (like an inverted spike). Do you think that this 
>> lack of data can trigger the bug you are working on? I don't have the 
>> same IO graph on my system, where the HDHomeRun is plugged straight 
>> into the 1 Gbps switch. In any case, we will move his HDHomeRun today 
>> so that it also goes straight to the switch.
>> On your current fix (that breaks FE/BE combo), I would be happy to 
>> test that if that is useful to you. I know something else will come 
>> out in the end, but it would certainly be super if I can get my 
>> friend's system stable (he is not doing FE/BE combo) and start 
>> focusing on something else during the weekends;-)
>> Cheers,
>> // Jonas
> The difference in the logs of my friend's backend is that he has many 
> many
> =>  D TFWWrite threadedfilewriter.cpp:489 (DiskLoop) 
> TFW(/data1/Recordings/2655_20140222010733.mpg:49): write(65424) cnt 0 
> total 0
> *cnt 0 total 0*. I don't have any of those on my system, even though I 
> ran with debug enabled watching live TV a full evening. I guess this 
> means that the writer thread doesn't have anything to write. Who is 
> feeding this guy? Where does the RTP(UDP) stream from the HDHomeRun 
> fit in? Sorry for all the questions. I am just trying to understand 
> how this is put together and if I am chasing a red herring with the 
> HDHomeRun network thingy
> // Jonas
We made changes to that the HDHomeRun is now directly connected to the 1 
Gbps switch. I still get those *cnt 0 total 0* messages but not as 
frequent. The IO graph looks much better without any huge dips. Time 
will tell....

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